1. Field of the Invention
The field of the invention is that of array antennas and more particularly that of reflector array antennas.
2. Description of the Prior Art
There are two large families of array antennas, namely phased array antennas (PAA) and reflector array antennas (RAA).
Array antennas must be reconfigurable in order to move from one coverage area (“spot”) to another.
In the case of phased array antennas, reconfigurability may be obtained by dividing the array into subarrays each associated with an active phase control device. The reconfigurability of the antenna then depends on only one constraint, namely the dimensions of each subarray, which depend on the dimensions of the coverage area to which the antenna must point.
In the case of reflector array antennas, it is essential that the radiating elements intercept with minimum losses the waves carrying the transmitted signals, which are delivered by a source. Now, the angle of incidence at which the radiating elements receive the waves varies as a function of their positions relative to the source. For certain arrays it may vary from 0° to 50°. An angular variation of this magnitude makes it particularly difficult both to receive waves coming from the source with a high gain and to transmit (or send) received waves over the whole of the pointed to coverage area with a high gain.
Reflector array antennas therefore routinely employ relatively undirectional radiating elements, with a typical dimension from 0.6λ to 0.7λ, where λ represents the operating wavelength. Reconfiguring the antenna diagram of this kind of antenna therefore necessitates equipping each radiating element with a phase control device. However, this kind of solution may lead to prohibitive costs.
Thus an object of the invention is to improve on this situation in the case of reflector array antennas.